A production process for producing a film, especially a functional film includes various drying steps such as drying after cleaning and drying after coating.
In a case where a separator film to be used as a functional film in a lithium ion secondary battery is taken as an example, Patent Literature 1 discloses a technique for providing one side of a film with a layer for achieving higher heat resistance. Specifically, Patent Literature 1 discloses a technique for coating a film with a heat-resistant coating solution by use of a coating device and thereafter causing the coated film to pass through a drier so as to dry the coated film.